Skip to main content
Log in

Electron transfer between the spinach plastocyanin mutant Leu12His and Photosystem 1

  • Published:
Photosynthesis Research Aims and scope Submit manuscript

Abstract

A spinach plastocyanin (Pc) mutant, Pc(Leu12His), has been constructed by site-directed mutagenesis and expressed in Escherichia coli to probe the importance of the hydrophobic patch in the interaction with Photosystem 1. The mutant has been characterized by optical absorption, EPR spectroscopy and redox titration. The electron transfer to Photosystem 1 was investigated by flash-induced time-resolved absorption measurements at 830 nm. The Pc(Leu12His) mutant showed a major change in the Photosystem 1 kinetics compared to wild-type Pc. In contrast to the biphasic Photosystem 1 reduction observed for the physiological reaction partner, only the slow phase was discerned when Pc(Leu12His) replaced wild-type Pc as the electron donor. The reaction showed a hyperbolic dependence with increasing Pc concentration, saturating at a rate constant value of 2000 s-1, which is about 10 times slower than the corresponding rate constant for wild-type Pc. Obviously, this position i s critical for a proper reaction. Moreover, the reaction showed a titrating behavior with a pKa of 6.7. Thus, it appears that both shape and charge of the residue in this position are important. A plausible reaction mechanism for electron transfer between wild-type Pc and Photosystem 1 is discussed. The role of electrostatic interactions may be that of long-range guidance and initial recognition that allow the two proteins to seek a pre-docking configuration(s). Then a short-range rearrangement(s), involving also hydrophobic interactions, forms an optimum docking configuration prior to electron transfer.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  • Boardman NK (1971) Subchloroplast fragments: digitonin method. Methods Enzymol 23: 268–276

    Google Scholar 

  • Bottin H and Mathis P (1985) Interaction of plastocyanin with the Photosystem I reaction center: A kinetic study by flash absorption spectroscopy. Biochemistry 24: 6453–6460

    Google Scholar 

  • Colman PM, Freeman HC, Guss JM, Murata M, Norris VA, Ramshaw JAM and Venkatappa MP (1978) X-ray crystal structure analysis of plastocyanin at 2.7 Å resolution. Nature 272: 319–324

    Google Scholar 

  • Gross EL (1993) Plastocyanin: Structure and Function. Photosynth Res 37: 103–116

    Google Scholar 

  • Haehnel W, Jansen T, Gause K, Klösgen R, Stahl B, Michl D, Huvermann B, Karas m and Herrmann RG (1994) Electron transfer from plastocyanin to photosystem I. EMBO J 13: 1028–1038

    PubMed  Google Scholar 

  • He S, Modi S, Bendall DS and Gray JC (1991) The surface-exposed tyrosine residue Tyr83 of pea plastocyanin is involved in both binding and electron transfer reactions with cytochrome f. EMBO J 10: 4011–4016

    PubMed  Google Scholar 

  • Hervas M, Navarro JA, Diaz A, Bottin H and De la Rosa MA (1995) Laser-flash kinetic analysis of the fast electron transfer from plastocyanin and cytochrome c 6 to Photosystem I. Experimental evidence on the evolution of the reaction mechanism. Biochemistry 34: 11321–11326

    PubMed  Google Scholar 

  • Kannt A, Young S and Bendall DS (1996) The role of acidic residues of plastocyanin in its interaction with cytochrome f. Biochim Biophys Acta 1277: 115–126

    Google Scholar 

  • Katoh S, Shiratori I and Takamiya A (1962) Purification and some properties of spinach plastocyanin. J Biochem 51: 32–40

    PubMed  Google Scholar 

  • Lee BH, Hibino T, Takabe T and Weisbeek PJ (1995) Site-directed mutagenetic study on the role of negative patches on silene plastocyanin in the interactions with cytochrome f and photosystem I. J Biochem 117: 1209–1217

    PubMed  Google Scholar 

  • Modi S, Nordling M, Lundberg LG, Hansson Ö and Bendall DS (1992a) Reactivity of cytochromes c and f with mutant forms of spinach plastocyanin. Biochim Biophys Acta 1102: 85–90

    PubMed  Google Scholar 

  • Modi S, He S, Gray JC and Bendall DS (1992b) The role of surface-exposed Tyr 83 of plastocyanin in electron transfer from cytochrome c. Biochim Biophys Acta 1101: 64–68

    Google Scholar 

  • Nordling M, Sigfridsson K, Young S, Lundberg LG and Hansson Ö (1991) Flash-photolysis studies of the electron transfer from genetically modified spinach plastocyanin to Photosystem I. FEBS Lett 291: 327–330

    PubMed  Google Scholar 

  • Pascher T, Karlsson BG, Nordling M, Malmström BG and Vänngård T (1993) Reduction potentials and their pH-dependence in site-directed-mutant forms of azurin from Pseudomonas aeruginosa. Eur J Biochem 212: 289–296

    PubMed  Google Scholar 

  • Pearson Jr. DC, Gross EL and David ES (1996) Electrostatic properties of cytochrome f: Implications for docking with plastocyanin. Biophys J 71: 64–76

    PubMed  Google Scholar 

  • Redinbo MR, Yeates TO and Merchant S (1994) Plastocyanin: structural and functional analysis. J Bioenerg Biomembr 26: 49–66

    PubMed  Google Scholar 

  • Reichert J, Altschmied L, Klösgen RB, Herrmann RG and Haehnel W (1995) Interaction of spinach plastocyanin with Photosystem I. In: Mathis P (ed) Photosynthesis: From Light to Biosphere, Proceedings of the Xth International Photosynthesis Congress, Vol II, pp 693–696. Kluwer Academic Publishers, Dordrecht, The Netherlands

    Google Scholar 

  • Sigfridsson K (1997) Ionic strength and pH dependence of the reaction between plastocyanin and Photosystem 1. Evidence of a rate-limiting conformational change. Photosynth Res 54: 143–153

    Google Scholar 

  • Sigfridsson K (1998) Plastocyanin-an electron-transfer protein. Photosynth Res 57: 1–28

    Google Scholar 

  • Sigfridsson K, Hansson Ö, Karlsson BG, Baltzer L, Nordling M and Lundberg LG (1995a) Spectroscopic and kinetic characterization of the spinach plastocyanin mutant Tyr83His: A histidine residue with a high pK value. Biochim Biophys Acta 1228: 28–36

    Google Scholar 

  • Sigfridsson K, Hansson Ö and Brzezinski P (1995b) Electrogenic light reactions in Photosystem I: Resolution of electron-transfer rates between the iron-sulfur centers. Proc Natl Acad Sci USA 92: 3458–3462

    PubMed  Google Scholar 

  • Sigfridsson K, Hansson Ö and Brzezinski P (1995c) Electrogenic light reactions in Photosystem I: Effects of plastocyanin, methyl viologen and dithionite on a 100 nanosecond to 100 millisecond time scale. In: Mathis P (ed) Photosynthesis: From Light to Biosphere, Proceedings of the Xth International Photosynthesis Congress, Vol II, pp 79–82. Kluwer Academic Publishers, Dordrecht, The Netherlands

    Google Scholar 

  • Sigfridsson K, Young S and Hansson Ö (1996a) Structural dynamics in the plastocyanin-Photosystem 1 electron-transfer complex as revealed by mutant studies. Biochemistry 35: 1249–1257

    PubMed  Google Scholar 

  • Sigfridsson K, He S, Modi S, Bendall DS, Gray JC and Hansson Ö (1996b) A comparative flash-photolysis study of electron transfer from pea and spinach plastocyanin to spinach Photosystem 1. A reaction involving a rate-limiting conformational change. Photosynth Res 50: 11–21

    Google Scholar 

  • Sigfridsson K, Sundahl M, Bjerrum MJ and Hansson Ö (1996c) Intraprotein electron transfer in a ruthenium-modified Tyr83-His plastocyanin mutant: Evidence for strong electronic coupling. J Biol Inorg Chem 1: 405–414

    Google Scholar 

  • Sigfridsson K, Young S and Hanson Ö (1997) Electron transfer between spinach plastocyanin mutants and Photosystem 1. Eur J Biochem 245: 805–812

    PubMed  Google Scholar 

  • Sigfridsson K, Ejdebäck M, Sundahl M and Hansson Ö (1998) Electron transfer in ruthenium-modified spinach plastocyanin mutants. Arch Biochem Biophys 351: 197–206

    PubMed  Google Scholar 

  • Sinclair-Day JD, Sisley MJ, Sykes AG, King GC and Wright PE (1985) Acid dissociation constants for plastocyanin in the CuI state. J Chem Soc Chem Commun 1985: 505–507

    Google Scholar 

  • Soriano GM, Ponamarev MV, Tae G-S and Cramer WA (1996) Effect of the interdomain basic region of cytochrome f on its redox reactions in vivo. Biochemistry 35: 14590–14598

    PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Sigfridsson, K. Electron transfer between the spinach plastocyanin mutant Leu12His and Photosystem 1. Photosynthesis Research 59, 243–247 (1999). https://doi.org/10.1023/A:1006170421534

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1023/A:1006170421534

Navigation